Electron discharge device



Sep tQ 17, 1946. G R KILGQRE 2,407,705

ELECTRON DISCHARGE DEVIQE Filed April 24, 1942 2 sheets-sheet 1 1 p 1 1946- I e. R. KILGORE" v 2,467,75

ELECTRON DISCHARGE DEVICE Filed April 24, 1942 2 Sheet-Sheefh 2 Patentecl Sept. 17, 194-6 ZAMJGS ELECTRON DISCHARGE DEVICE George Ross'Kilgore, Verona, N; 3;, assignor to Radio Corporation of Americana corporation of Delaware Application April 24, 1942, Serial No. 440,298

19 Claims. 1

My invention relates to electron discharge devices utilizing periodic electron beam deflection and particularly useful at ultra high frequencies.

In conventional electron discharge devices of the type under consideration, a beam of electrons is directed between a pair of deflecting electrodes toward an apertured electrode, behind which is usually placed a collector. Alternating high frequency voltages are applied to the deflecting electrodes to cause the electron beam to be de-' flected across the aperture to thus control the instantaneous flow of electron current to the collector, which may be used as an output electrode. In such conventional types of tubes the deflecting sensitivity drops off as the frequency at which the tube is operated is increased due to electron transit time effects. Efforts have been made to increase the deflection sensitivity or the transconductance of the tube but such efforts have not met'with a great deal of success. Conventional tubes of this kind are also subject to the limitation that when operated at ultra high frequencies the input circuit tends to be of low' resonant impedance resulting in an excessive amount of power being required to drive the tube. This decreases the effective power gain of the tube when operated as an amplifier, Fundamental causes of low resonant impedance include, among other things, radiation and resistance losses due to high circulating current in electrodes and leads; Electron loading also results from the interaction of the electron stream and the circuits connected to the tube and electrodes and may cause undesired degenerative and regenerative effects caused by lead impedances common to more than one circuit.

It is an object of my invention to provide an electron discharge device of the beam deflection type, which is particularly suitable for use at ultra high frequencies and which has a comparatively high transconductance.

It is another object of my invention to provide such a device utilizing an input circuit having high resonant impedance, thus making more effective the use of the driving power.

A further object of my invention is to provide such a device in which undesired coupling due to common leads and ineffective shielding between circuits. is reduced to a minimum.

Another specific object of, my invention is to provide an electron discharge device of the beam deflection type, utilizing multiple additive deflection for providing a tube having high transconductance.

A still further object of my invention is to provide an electron discharge device of the beam deflection type utilizing additive multiple deflection and secondary emission amplification for.

producing a tube having very high transconductance.

A still further objector" my invention is to. provide an electron discharge device of the beam deflection type utilizing a novel type of combined electrode system and circuit useful at ultra high frequencies and having a high transconducta-nce.

The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims, but the-in- Vention itself will best be understood by reference to the following description taken in connection with the accompanying drawings in which Figure 1 is a longitudinal section of one form of'an electron discharge device made according to my invention and its associated circuit, Figure 2. is a transverse section taken along the line 22 of Figure 1, Figure 3 is a longitudinal section of a modification of an electron discharge device made according to my invention, Figure 4 is a transverse section taken along the line 4.4 of Figure-3, Figure- 5 is an enlarged sectional view taken along the line 5-5 of Figure 3, Figure 6'isa perspective of the electrode system and high frequency circuit made according to my invention and utilized in the tube shown in Figure 3, and Figure 7 is a schematic longitudinal section of the tube shown in Figure 3 made according to my invention and a diagram of its associated circuit.

Referring to Figure 1, an electron discharge device made according to my invention includes an evacuated envelope lil having the usual press H and base l2. Supported from this press is the indirectly heated cathode 13 provided with leads 13 which act as the cathode lead and heater leads. Mounted at the other end of the envelope is a collector l4 toward which the beam is directed through the intermediate electrodes positioned between the cathode and collector.

Adjacent the cathode is the apertured beam forming and focusing electrode in the form of a disc 15 electrically connected to the lead I5. The deflecting electrode system includes the tubular member [6 separated into compartments or chambers by means of the transverse conducting elements ll, I8 and I9 provided with the aligned apertures IT, IS and i9 through which the beam from the cathode is directed during operation of the electron discharge device. The beam in passing through this deflecting electrode system passes through another apertured electrode 20 having the aperture 20 and connected to the lead and support 2!. Positioned between this apertured electrode and the collector is the electron multiplying system comprising electrodes 22, 23, 2Q, 25, 26 and screen 21. The element 20 maintained at ground potential by being connected to electrode 25 causes the beam to be directed against the surface of the element 22 to cause the emission of secondary electrons when struck by the beam of primary electrons. These electron multiplying electrodes may be coated with the usual material for inducing a high ratio of primary-to-secondary electrons.

In accordance with my invention, I position between the apertured conducting members [8 and ii) the successively positioned oppositely disposed deflecting electrode elements 3F 3! and 32.. The distance between the centers of these deflecting elements is equal to the distance traveled by an electron during a half period of the controlling voltage applied to these deflecting electrodes. Thes elements preferably. have a dimension in the direction of travel of the electron beam equal approximately to the distance travelled by an electron during a half period or 7r radians. The successive elements are cross connected so that the phase relationship between the electron beam and the voltage applied to the controlling electrode elements will cause additive deflection, that is deflection in the same direction.

The lines 35 and. 35 are connected to the signal input circuit as shown and to the voltage divider arrangement 33 through the resistance 3'! and 38 which cooperate with the shorting condenser 56. This arrangement permits not only tuning of the lines 34 and 35 but provides the necessary direct voltages for applying the proper biasing or polarizing voltages to the deflecting electrodes to center the electron beam. The proper positive voltage is applied to deflecting electrode system I6 by means of the conductor 3:3, and the voltage source for the multiplier elements is shown at 48, the voltages increasing in a positive direction from the apertured member 725 to the collector l4. By-passing condensers, such as All, provide paths for the radio frequency currents. The output is taken between collector M and screen 21 across the circuit comprising the primary of transformer 42 and condenser 63, the proper biasing voltage on the collector being provided by means of con ductor 43, by-passing condenser 44 completing the radio frequency circuit and permitting different positive voltages to be applied to the member and the collector [6.

In operation a beam of electrons is directed from the cathode i3 through the beam forming and electron lens system formed by elements i5 and elements ll and I8. By properly positioning deflecting elements 35 with respect to apertured elementl8 another electron lens can be provided between these elements to properly focus the beam on the aperture l9 of apertured element 59. The beam may also be properly directed by applying the bias to the three deflecting elements, an odd number of elements being provided for this purpose. The beam is deflected across aperture it when an input signal voltage or control voltage is applied through the conductors and 35. The transit time of the electrons is so matched to the deflecting elementsthat any electrons which may have been deflected in an upward direction by deflecting electrodes 35 will arrive between elements 3! a half period later and again be deflected in the same direction,

deflected in the same direction. Sinc the elements are cross-connected and since centers are positioned a half period apart, the voltages between deflecting electrodes will always be in the proper phase to cause additive deflection of any group of electrons in the same direction.

The amount of deflection across apertured element I9 at any particular instant determines the amount of current flowing through the aperture so that the input voltage may be reproduced and the output much amplified because of the high transconductance of the tube. This amplification is still further increased by means of the multiplier system positioned between the apertured member 2!] and collector 14, the output being taken between the collector l4 and screen 27 by means of the output circuit comprising transformer 52 and condenser 43. If it is desired to utilize the device as a converter it would be possible to do this by introducing both signal and local oscillator voltages on the input or Lecher wires 34 and 35.

In Figure 3 is shown a modification of my invention in which the input circuit is self-contained and in which the input circuit is substantially completely shielded from the cathode electrode as well as the output electrode system. This input circuit incorporates a modified form of the multiple deflection arrangement shown in Figure 1.

In this embodiment the evacuated envelope 50 is provided with the usual press 5| and base 5|. Supported on the press is an indirectly heated cathode 52 provided with a cathode lead 53. Next adjacent the cathode is the beam forming and focusing electrode 54 supported by means of a glass bead support construction 54. The electrode 54 and cathode 52 are electrically connected as shown in Figure 5. Mounted at the other end of the envelope is the collector 55 provided with supporting leads 55. Positioned between the focusing electrode 54 and collector 55 is the beam deflecting electrode system comprising the tubular member 56 having extending thereacross the apertured disc-like conducting elements or partitions 5?, 58 and 59 provided with the elongated slots 5?, 58 and 59 which are aligned with each other and with the aperture 54 in the focusing element 54. Th length of these elongated slots varies as shown for the purpose of properly forming the beam.

In accordance with my invention the deflecting electrode system and input circuit are combined into a unitary structure which simplifies the construction and permits eiiective shielding of the input circuit and electrodes from the output electrode system. The tubular member 56 is provided with the extensions 60 and BI and it is within these extensions that the combined deflecting electrode system and circuit are mounted and supported by means of glass bead supporting structures 63 and 63.

As best shown in Figure 6, the deflecting electrode system comprises an elongated rectangularly shaped member of ribbon-like construction having intermediate its ends inwardly extending sections 64 provided with slots 85 for forming deflecting elements 64 between said slots. The distance from the center line extending transversely of the slotted portion to an end of the rectangularly shaped member is equal to a quarter-wave of the received or controlling voltage, so that in effect each half acts like a Lecher wire system of quarter wave-length, the voltage peak likewise arriving between elements 32 to be again appearing between the inwardly extending portions -fi l in-which the deflecting electrode elements are positioned, The voltage is fedto this circuit arrangementbymeans of leads 66 which may be connected to a transmission line system, for example, of the coaxial cable type. The distance between centers of the elements 64 is equal to the distancethatan electron travels during one'periodof the applied controlling voltage or electrically to 25+ radians, the elements having awidth in the direction of travel of the electron beam substantially equal to a half-period or 1r radians. This arrangement makes it possible to connect all elements on'the same side of the beam, electrically together, and to the same side of th'e'L'echer wire system formed by the structureG'ZQ To-properly center the beambetween the deflectingelectrode elements andto direct it through the apertured-member' 59, I provide a pair of beam directingelements 6! in the chamber between partitions-5i and 58," the'proper biasing voltages being applied by means of the leads 68.

The schematic wiring diagram-shownin Figure '7 illustratesthe connections to the voltage divider system H and the voltage or potential source Him the beam directing electrodes 61 and" the various other electrodes. The output is takenbetween the collector 55' and the transverse conducting member 59 supported by tubularelement 5% across the inductance element 12. It'will be observed that a wire or conductor 591 is positioned centrally of the aperture toprovide the double apertured efiect for obtainingthe desired output 1 characteristics.

In operation the electron beam formed by cathode 52- and-focusing element 56 is directed through aperture 5?" between the beam directingelements 6?, upon which the bias may be properly adjusted to center the beam on aperture 58" and to direct it through the deflecting electrode system between'the pairs of successively positioned oppositely disposed beam deflecting elements Ed. As the electron beam passes between the elements it comes under the influence of each successive pair of elements forapproximately a half period at half-period intervals. Inasmuch as the voltage. during the half-period intervals passes through 180, deflection of the beam will be additiveo'r in the same direction, thus efiec tive transconductance is increased substantially in direct ratio to the number of successive pairs of deflecting elements. In the arrangement shown the input circuit is combined with the deflecting elements to greatly simplify this strucrare; to make more efiective the deflection contrbL-and because of the shielding arrangement of the tubular member 56 and extensions 69 and G l the input circuit is well shielded from the output electrode system, so that little if any inter-' action results.

While I' have indicated the preferred embodiments of'my invention of which Iam now aware and have also indicated only one specific application'for which my invention may be employed, it will be apparent that my invention is by no means limited to the exact forms illustrated or the use indicated, but that many variations may be made inthe particular structure used and the purpose for which it is employed without departing from the scope of my invention as set forth in the appended claims.

WhatI claim as new is:

1 An eleotron discharge device having cathode means for providing a directed beam of electrons and an output electrodesystem for" receiving: said electrons, andmeans positioned between the cathode means and the output electrode 7 system through whichsaid: electron loe'arn' is directed,

and includinga plurality of'successive pairsof oppositely disposed deflecting elements between which'th'e beamis directed, said 'elemen'ts being adapted 'to'liave an alternating control voltage of high frequency applied thereto, the spacing between the centers of' the elements of different pairs being equal to the distance travelled by an electron during a cycle of the applied controlling voltage.

2. An electron discharge device having cathode means for providing a directed beam of electrons;

and an output electrode system for receiving said electrons, and means positioned between the cathode means and the output electrode system" through which said electron beam is directed? and including a plurality of successive'pairs of 'oppo-- sitely disposed deflecting elements between which the beam is directed, saidelements being adapted to have an alternating control voltage of high frequency applied thereto, the spacing between the centers of the elements of different'pairs being equal to the distance travelled by an electron during a cycle of the applied controlling voltage, all of the elements on the'same side of the beampath being electrically connected together.

3. An electron discharge device having cathode means for providing a directed beam of electrons and an output electrode system for receiving said electrons, and means positioned between the cathode means and the output electrode system through which said electron beam is directed, and including a plurality of successive pairs of op"po-" sitely disposed deflecting elements between which the beam is directed, said elements being adapted' to have an alternating control voltage of high frequency applied thereto, the spacing between the centers of the elements of different pairs being equal to' the distance travelled by an electron during a cycle of the applied controllingl voltage, allof the elements on the same side of the beam path being electrically connected together, and a conducting loop connected between the elements on opposite sides of the beam" means, and including a pluralit of successive pairs of oppositely disposed deflecting elements adapted to have an alternating control voltage of high frequency applied thereto, the spacing between the centers of the elements being equal to the distance travelled by an electron in a cycle of the applied controlling voltage, each pair of deflecting elements being spaced from the next' succeeding pair of elements a distance equal to the dimension of said elements in the direction of travel'of the electron beam.

5 An electron discharge device having a cath ode for supplying a beam of electronsand an output electrode system toward which said electrons are directed, and means positioned between the cathode and the output electrode system for subjecting said beam to additive successive deflection and including a conducting enclosure through which the beam of electrons is directed, said conducting enclosure having transverse ele-" ments provided with aligned apertureaanq a plurality of successive pairs of oppositely disposed deflecting elements positioned between the transverse elements and between which said beam of electrons is directed during operation of said electron discharge device, the spacing between the centers of said elements being equal to the distance travelled by an electron in a cycle of the applied alternating control voltage said output electrode system including an apertured electrode through which the beam of electrons is directed, and a plurality of secondary emitting electrode elements upon which said beam is directed.

6. An electron discharge device having a cathode means for supplying a directed beam of electrons, and an output electrode system toward which said electrons are directed, a tubular conducting member positioned between the cathode and output electrode system through which said beam is directed, and having a plurality of transverse conducting elements having apertures aligned and through which the beam of electrons is directed, and a plurality of successively positioned pairs of deflecting electrode elements positioned between the transverse apertured elements, said pairs of deflecting electrode elements being cross connected with the next succeeding pair of deflecting electrode elements.

7. An electron discharge device having a cathode means for supplying a directed beam of electrons, and an output :electrode system toward which said electrons are directed, a tubular conducting member positioned between the cathode and output electrode system through which said beam is directed, and having a plurality of transverse conducting elements having apertures aligned and through which the beam of electrons is directed, and a pluralit of successively positioned pairs of deflecting electrode elements positioned between the transverse apertured elements, said pairs of deflecting electrode elements being cross connected with the next succeeding pair of deflecting electrode elements, said output electrode system including an apertured electrode and a collector.

8; An electron discharge device having a cathode means for supplying a directed beam of electrons, and an output electrode system toward which said electrons are directed, a tubular conducting member positioned between the cathode and output electrode system through which said beam is directed, and having a plurality of transverse conducting elements having apertures aligned and through which the beam of electrons is directed, and a plurality of successively positioned pairs of deflecting electrode elements positioned between the transverse apertured elements, said pairs of deflecting electrode elements being cross connected with the next succeeding pair of deflecting electrode elements, said output electrode system including a secondary electron emitting means.

9. An electron discharge device having a cathode means for supplying a directed beam of electrons, and a collector toward which said electrons are directed, and a deflecting electrode means positioned between the cathode means and the collector and including a conducting enclosing member having a plurality of transverse elements provided with aligned apertures through which said beam of electrons is directed, and a deflecting electrode system within said conducting enclosing member and comprising an elongated rectangular shaped conducting loop having intermediate its ends a plurality of oppositely disposed slots formin a plurality of oppositely' disposed deflecting elements through which the beam of electrons is directed.

10. An electron discharge device having a cathode means for supplying a directed beam of electrons, and a collector toward which said electrons are directed, and a deflecting electrode means positioned between the cathode means and the collector and including a conducting enclosing member having a plurality of transverse elements provided with aligned apertures through which said beam of electrons is directed, and a deflecting electrode system comprising an elongated rectangular shaped conducting loop having intermediate its ends a plurality of oppositely disposed slots for forming a plurality of oppositely disposed deflecting elements through which the beam of electrons is directed, said conducting loop lying within said conducting enclosing member and extending through the sides of the conducting enclosing member and extensions on said conducting enclosing member for shielding the ends of said conducting loop.

11, An electron discharge device having a cathode means for supplying a directed beam of electrons, and a collector toward which said electrons are directed, and a deflecting electrode means positioned between the cathode means and the collector and including a conducting enclosing member having a plurality of transverse elements provided with aligned apertures through which said beam of electrons is directed, and a deflecting electrode system comprising an elongated rectangular shaped conducting loop having intermediate its ends a plurality of oppositely disposed slots for forming a plurality of oppositely disposed deflecting elements through which the beam of electrons is directed, said conducting loop lying within and extending through the sides of the conducting enclosing member and extensions on said conducting enclosing member for shielding the ends of said conducting loop, and a pair of beam directing electrodes positioned between the cathode means and the deflecting electrode system.

12. An electron discharge device having cathode means for supplying a directed beam of electrons and electrode means for receiving said beam of electrons, an apertured element positioned adjacent the receiving electrode means and having an aperture registering with said receiving electrode means, a deflecting electrode system positioned between the cathode means and the apertured means and including an elongated rectangularly shaped conducting member through which the beam of electrons is directed, and having slots on opposite sides of said member intermediate the ends of said member for providing a plurality of successiv ly positioned oppositely disposed pairs of deflecting elements between which said beam passes.

13. An electron discharge device having cathode means for supplying a directed beam of electrons and electrode means for receiving said beam of electrons, an apertured element positioned adjacent the receiving electrode means and having an aperture registering with said receiving electrode means, a deflecting electrode system positioned between the cathode means and the apertured means and including an elongated rectangularly shaped conducting member through which the beam of electrons is directed, said member having slots on opposite sides intermediate the ends of said member for providing a plurality of successively positioned oppositely disposed pairs of deflecting elements between which said beam passes, the distance between centers of successive pairs of deflecting elements being equal to the distance travelled by an electron during a cycle of the applied controlling voltage.

14. An electron discharge device having cathode means for supplying a directed beam of electrons and electrode means for receiving said beam of electrons, an apertured element positioned adjacent the receiving electrode means and having an aperture registering with said receiving electrode means, a deflecting electrode system psitioned between the cathode means and the apertured means and including an elongated rectangularly shaped conducting member through which the beam of electrons is directed, said member having slots on opposite sides intermediate the ends of said member for providing a plurality of successively positioned oppositely disposed pairs of deflecting elements between which said beam passes, and means including rod-like elements positioned between the cathode means and deflecting electrode system for controlling the direction of the electron beam between the oathode and the deflecting electrode system.

15. An electron discharge device having cathode means for supplying a directed beam of electrons and electrode means for receiving said beam of electrons, an apertur-ed element positioned adjacent the receiving electrode means and having an aperture registering with said receiving electrode means, a deflecting electrode system positioned between the cathode means and the apertured means and including an elongated rectangularly shaped conducting ribbon-like loop through which the beam of electrons is directed, said loop having slots on opposite sides intermediate the ends of said loop for providing a plurality of successively positioned oppositely disposed pairs of deflecting elements between which said beam passes, the loop having thickened portions in which said slots are formed.

16. An electron discharge device having a cathode for supplying electrons, and means for forming said electrons into a directed beam, and means for receiving said beam, means intermediate said beam forming means and said beam receiving means and including a tubular member having its longitudinal axis coinciding with the path of the electron beam and provided with a plurality of transverse conducting members having aligned apertures through which the beam is directed, a pair or" beam directing electrodes positioned between two of said transverse conducting members and a beam deflecting electrode system positioned between another pair of transverse conducting members, and including an elongated rectangularly shaped conducting loop extending through opposite sides of the tubular member and having a plurality of successively positioned deflecting electrode elements intermediate the ends of said loop and positioned on opposite sides of the path of said electron beam, and shielding extensions supported on said tubular member and surrounding the ends of said conducting loop.

17. An electron discharge device having a cathode for supplying electrons, and means for forming said electrons into a directed beam, and means for receiving said beam, means intermediate said beam forming means and said beam receiving means and including a tubular memher having its longitudinal axis coinciding with the path of the electron beam between the oathode and the receiving means and provided with a plurality of transverse conducting members having aligned apertures through which the beam is directed, and a beam deflecting electrode system positioned between a pair of said transverse members, and including an elongated rectangularly shaped conducting loop extending through opposite sides of the tubular member and having a plurality of successively positioned deflecting electrode elements intermediate the ends of said loop and positioned on opposite sides of the path of said electron beam, and shielding extensions supported on said tubular member and surrounding the ends of said conducting loop.

18. An electron discharge device havin a cathode for supplying a beam of electrons, and means for receiving said beam of electrons, an apertured transverse conducting member between said cathode and means for receiving said beam of electrons, a beam deflecting electrode system positioned between the apertured conducting memher and said cathode, and including an elongated rectangularly shaped conducting loop having a plurality of successively positioned oppositely disposed slots on opposite sides thereof forming a plurality of deflecting electrode elements intermediate the ends of said loop and between which elements the electron beam is directed during operation of said electron discharge device.

19. An electron discharge device having cathode means for providing a directed beam of electrons, and an output electrode system for receiving said electrons, means positioned between the cathode means and the output electrode system through which the electron beam is directed and including a plurality of successive pairs of oppositely disposed deflecting electrodes through which said beam is directed, said elements being adapted to have an alternating control voltage of high frequency applied thereto, the spacing between the elements of different pairs being equal to the distance travelled by an electron during a multiple of cycles of the applied controlling voltage.

GEORGE ROSS KILGORE. 

